Steering assistance control apparatus

1. A steering assistance control apparatus, comprising:

a positional deviation calculator that calculates a lateral positional deviation between an own vehicle and a preceding vehicle based on a detection signal from a sensor;

a relative yaw angle calculator that

calculates a first relative yaw angle formed by a first traveling direction of the own vehicle and a first traveling direction of the preceding vehicle at a first time period, and

calculates a second relative yaw angle formed by a second traveling direction of the own vehicle and a second traveling direction of the preceding vehicle at a second time period, wherein the second time period follows consecutively after the first time period;

a target value calculator that

determines a first polarity of the first relative yaw angle and a second polarity of the second relative yaw angle,

compares the first polarity of the first relative yaw angle to the second polarity of the second relative yaw angle, and

detects a polarity inversion between the first polarity of the first relative yaw angle and the second polarity of the second relative yaw angle based on determining that the first polarity of the first relative yaw angle differs from the second polarity of the second relative yaw angle based on the comparison,

calculates, in response to detecting a polarity inversion between the first polarity and the second polarity, a steering control target value based on the lateral positional deviation, the second relative yaw angle, and the detected polarity inversion; and

a steering driver that reduces a control amount of steering and drives a steering mechanism based on the steering control target value.

2. The steering assistance control apparatus according to claim 1 ,

wherein the target value calculator calculates the steering control target value in accordance with magnitude of an absolute value of the second relative yaw angle.

3. The steering assistance control apparatus according to claim 1 ,

wherein the target value calculator calculates the steering control target value based on the polarity inversions occurring on shorter cycles.

4. The steering assistance control apparatus according to claim 2 ,

wherein the target value calculator calculates the steering control target value based on the polarity inversions occurring on shorter cycles.

5. The steering assistance control apparatus according to claim 1 ,

wherein the target value calculator calculates the steering control target value in accordance with a duration of time during which the second polarity of the second relative yaw angle is kept unchanged after the polarity inversion is detected.

6. The steering assistance control apparatus according to claim 2 ,

wherein the target value calculator calculates the steering control target value in accordance with a duration of time during which the second polarity of the second relative yaw angle is kept unchanged after the polarity inversion is detected.

7. The steering assistance control apparatus according to claim 3 ,

wherein the target value calculator calculates the steering control target value in accordance with a duration of time during which the second polarity of the second relative yaw angle is kept unchanged after the polarity inversion is detected.

8. The steering assistance control apparatus according to claim 4 ,

wherein the target value calculator calculates the steering control target value in accordance with a duration of time during which the second polarity of the second relative yaw angle is kept unchanged after the polarity inversion is detected.

9. The steering assistance control apparatus according to claim 1 ,

wherein the target value calculator utilizes a dead zone when determining the first polarity of the first relative yaw angle and the second polarity of the second relative yaw angle.

10. The steering assistance control apparatus according to claim 2 ,

wherein the target value calculator utilizes a dead zone when determining the first polarity of the first relative yaw angle and the second polarity of the second relative yaw angle.

11. The steering assistance control apparatus according to claim 3 ,

wherein the target value calculator utilizes a dead zone when determining the first polarity of the first relative yaw angle and the second polarity of the second relative yaw angle.

12. The steering assistance control apparatus according to claim 4 ,

wherein the target value calculator utilizes a dead zone when determining the first polarity of the first relative yaw angle and the second polarity of the second relative yaw angle.

13. The steering assistance control apparatus according to claim 5 ,

wherein the target value calculator utilizes a dead zone when determining the first polarity of the first relative yaw angle and the second polarity of the second relative yaw angle.

14. The steering assistance control apparatus according to claim 6 ,

wherein the target value calculator utilizes a dead zone when determining the first polarity of the first relative yaw angle and the second polarity of the second relative yaw angle.

15. The steering assistance control apparatus according to claim 7 ,

wherein the target value calculator utilizes a dead zone when determining the first polarity of the first relative yaw angle and the second polarity of the second relative yaw angle.

16. The steering assistance control apparatus according to claim 8 ,

wherein the target value calculator utilizes a dead zone when determining the first polarity of the first relative yaw angle and the second polarity of the second relative yaw angle.

17. The steering assistance control apparatus according to claim 1 ,

wherein calculating the steering control target value further comprising:

calculating a first target steering angle based on the lateral positional deviation and the second relative yaw angle; and

calculating a second target steering angle based on the detected polarity inversion, the second target steering angle being smaller than the first target steering angle, and

wherein, when the target value calculator detects the polarity inversion between the first polarity of the first relative yaw angle and the second polarity of the second relative yaw angle while the steering driver drives a steering mechanism based on the first target steering angle, the steering driver changes driving the steering mechanism based on the first target steering angle to driving the steering mechanism based on the second target steering angle.

18. A steering assistance control apparatus, comprising:

a positional deviation calculator that calculates a lateral positional deviation between an own vehicle and a preceding vehicle based on a detection signal from a sensor;

a relative yaw angle calculator that

calculates a first relative yaw angle formed by a first traveling direction of the own vehicle and a first traveling direction of the preceding vehicle at a first time period,

calculates a second relative yaw angle formed by a second traveling direction of the own vehicle and a second traveling direction of the preceding vehicle at a second time period, wherein the second time period follows consecutively after the first time period, and

determines, utilizing a dead zone, a first polarity of the first relative yaw angle and a second polarity of the second relative yaw angle;

a target value calculator that, in response to detecting a polarity inversion between the first polarity and the second polarity, calculates a steering control target value based on 1) the lateral positional deviation, 2) the second relative yaw angle, 3) the polarity inversion occurring on shorter cycles, and 4) a duration of time during which the second polarity of the second relative yaw angle is kept unchanged after the polarity inversion is detected; and

a steering driver that reduces a control amount of steering and drives a steering mechanism based on the steering control target value.